Three US soldiers were killed and another was wounded by an Afghan soldier in eastern Afghanistan’s eastern Nangarhar province.

Three US soldiers were killed and another was wounded Saturday in eastern Afghanistan’s eastern Nangarhar province, the Pentagon said. An Afghan official said the deaths and injury stem from an attack by an Afghan soldier, who also died. In a statement from Washington, the Pentagon did not provide details about what led to the deaths of the US soldiers. It said the incident was under investigation. The wounded soldier had been evacuated for medical treatment, it said.

The Taliban claimed responsibility for the attack saying it was carried out by an infiltrator. Taliban spokesman Zabihullah Mujahid says in a statement that a Taliban loyalist had infiltrated the Afghan army “just to attack foreign forces.”

Mujahid claimed on Twitter that four US soldiers were killed in the attack.

A spokesman for the provincial governor in Nangarhar province, Attahullah Khogyani, said in a statement that the attack took place in the Achin district.

Khogyani told AFP that an Afghan commando had opened fire on US troops and was killed in return fire.

In March, an Afghan soldier was killed after he opened fire on foreign forces at a base in Helmand province, wounding three U.S. soldiers.

The "green-on-blue" attacks -- when Afghan soldiers or police turn their guns on international troops -- have been a major problem during NATO's battle alongside Afghan forces.

Most of the insider attacks stem from personal grudges and cultural misunderstandings rather than insurgent plots, western officials say.

Yesterday's attack came just hours after at least six Afghan policemen were wounded in an errant US air strike in southern Helmand province.

White House spokesman Raj Shah told reporters traveling with President Donald Trump in New Jersey that Trump was “following the emerging situation in Afghanistan.”